Heating device for concrete plants



y 12, 1932- R. w. F IEROH V HEATING DEVICE FOR CONCRETE PLANTS 18 :EzUGnZEr- 6017677 U]: 1 5M070, 7 4% 6% 60M Filed Dec. 6, 1950 Patented July 12, 1932 ROBERT W. FIEROH, OF CHICAGO, ILLINOIS HEATING DEVICE FOR CONCRETE PLANTS Application filed December a, 1930. Serial No. 509,458. I

This invention relates to the art ofconcrete mixing plants, and constitutes acontinuation in part of an application heretofore filed by me on the 8th day of July, 1929, Serial No; 37 6,7 92, Letters Patent N o.-1,802,34;0, April In the'apparatus disclosed in my aforesaid application there is mounted on a portable platform a materialbin divided by a false 10 bottom into a lower compartment adapted to contain bags of cement and an upper compartment or'hopper adapted to receive mineral, this latter, in theconstruction shown, employing a central vertical partition providing on one side thereof ahopper for crushed stone and on its other sidea hopper for sand.

Extending upwardly through one end of the material bin is a vertical conveyorcasing housing an endless bucket elevator and equipped at its upper end with a hinged discharge spout by which the'material may be delivered into either of the underlying crushed stone. and sand hoppers. The two hoppers areequipped at theirbottoms with discharge gates or valves by which the mineral ingredients are delivered through a guide chute into a mixer located in the lower compartment. r

In a concrete mixing plant of this type, which operates out of doors, it is desirable, andpractically necessary, to provide'some means for maintaining the mineral in the hopper or hoppers at a temperature above the freezing point, in order, thatthe apparatus may function in sub-freezing weather; and the object of the present invention is to provide a very'simple and highly eflicient'means for heating the mineral in thehopper without interfering with the free gravity flow thereof through the hopper and without occupying any appreciable hopper space.

tofore been proposed to heat the mineral in such hoppers by a blast of steam-directed ,therethrough, but a serious drawback to thls method lies in the fact that the moisture in the steam freezes, and makes a bad-matter worse, unless the supply of steamis continuously maintained both when theapparatus is operating and when it is .idle. Another object of the invention is to provide a heating It has here 9 NT" OFFICE means which will avoid the introduotionlof I portion of the hopper, the mineral being heated by radiation from said coil, and leading the discharge end of the coil into the casing of the elevating'conveyor, by which the residual heat remaining in the heating medium after it has passed through the coilis transferred to the buckets of the elevating con:

veyor and to the materialinsaid buckets. Torender this practical, without imparting molsture to the material in the conveyor buckets, the heating medium employed consists preferably of the hot'products of combustion from a Bunsen oil burner..

In order that, the improvement may be clearlyunderstood by persons skilled'in the art, I have, in'the accompanying drawing, illustrated so much of the concrete mixing plant: disclosed in my former application above identified as is necessary to illustrate the application thereto. ofthe material heatlng device, and referring thereto,

' F 1g. 1 is a sideelvation, partly in vertical section, of the portable plant; I

. Fig. 2 is a plan section, turned end for 'end, on line 2-2 of Fig. 1, and

' Fig. 3 is an'enlarged horizontal section through the lower section of the casing of the elevating conveyor, in the plane of the line 8-3of Fig. 1, showing in full lines the discharge end of the heating coil leading through one of the side walls of the conveyor casing. I

limit the description mainly to such partsof 1 "9, In the presentspecification I shall not attempt to describe the complete plant, but wi l form, superposed on which is a rectangular material bincomprising a lower section 13 anda removable upper section l l resting upon the lower section. The platform and superposed sectional material storage bin are shown of which slope downwardly to gate-controlled discharge openings 46 and .47 The space within the upper bin section 14 and the space within the lower bin section 18 above the false bottom is divided approximately centrally,ffor.the separate storage of sand and gravel or crushed'stone," by a removable vertical transversepartition 23', this partition ex= tending down to and between the discharge openings 46'and 47 in the false bottom. 7

Suitably builtintoon'e end of the lower bin section 13 is the lower, fixed section 24', of an upright elevator casing, superposed on which is an upper hingedsection 25. The inner or front wall of the upper section 25 is .pivotally joinedto and inregisterwith the inner or front wall of the lower section 24: by hingejlugs 26 and'a hinge rod 27 that is supportediby a pair of horizonta lly extending 'channel bars 28 overlying the lower bin section. For the purposesof the present invention, however,it is immaterial whether the conveyor casing be hinged, so as to be capable of-folding dowiiont'o the material bin, as indicated by dotted; linesin Fig. 1,-or be formed in one continuous length Journa-led in the upper and lower ends of the conveyor casing are the usual sprocket wheels 29 andeo over which is trained the usual endless bucket conveyor 31. At the lower end of the conveyor casing and communicating therewith is a material receiving hopper' '33.

The upper end of the conveyor casing is provided with the usual fiXeddischa-rge chute 4 0,. and to the latter is hinged at 41 an extension chute 42, which canvbe'lowered, as

shown infull lines in Fig. 1, to discharge gravel or crushed stone intothe correspond ing section of the storage bin, or can be raised to the dottedline position to permitv the disl bin'.

charge of sand through chute into the sand section of the storage bin., This extension chute is operated by a cable43. carried upwardly over the top. of the'conveyor casing and downwardly of the'rear side ofthe latter, its lower end being anchored to a pin 44 secured in aframe bar of the material storage The hopper discharge openingsefi and '47 registeriwith underlying spouts and"5 l which, through a guide chute 59, deliver the mineral to a mixer (not shown) in the lower' compartment. 13.

Coming now to a description of the means for heating the material both in the material .endof thisheaterpipe is connected a valvecontrolled supply pipe 79 leading from a kerosene pressure tank 80 mounted in one corner of the material bin, the upper end of the pipe 'ZQregistering with one end of the coil 78 and being equipped with a gas generating 'coil 79 and a perforated sleeve? 9 for the induction of air-to create a Bunsen flameJ The opposite end of the heater pipe- 78-, as best shown -in-Fig. 8, entersan opening 81 in one of the side f-wa'lls of the conveyor.- casing, whereby the flame and hot products of com bustion fiowingthrough the pipei78 project intothe conveyor casing and impart heat to the conveyor-and thematerial-being elevated thereby. 'The-p'ortions-of the coil? 8 extendingthro'ughthe'bin hopper are indirect contact with themat'er-ial in thelatter, and,--of course, radiate a large-amount-of heat tothe said material. The heating pipe orcoil being located substantially'at the bottom of: the

,hopper, thisiradiated heat naturally rises through andwarms up the mass of superposed material, thus preventing freezingand cakingoft the material in sub-freezing weather-. 7' I ltwillbe observed by reference to Fig, 3, that the-heating pipe 78' enters the conveyor casing at a'poi'ntf opposite theascending limb of; the conveyori l his" is an advantage, because the warm roducts of-combustion, which'tend to rise, merge into an ascending column of air caused by theupward travel of theconveyor chain and buckets; which would not be the case, were the heating pipe led into the casing at a point opposite the descending limb of the conveyon I -I amaware that ithas heretofore been proposed to line the vertical walls of a materi al 'hopper wi'th steampi'pes or coils; but such heating pipes do not possess the efficiency of horizontalpipesfor coils located in the bottom portion off-the'hopper and embedded inthe material 'stored; in the latter.

Bymy improved heater, the h atis distributed throughout practically. the entire cross "section iof" the mat'erial "and rises slowly through the latter, whi le suchheat as is; not

radiated to-the material inthe hopper is vpass'ed into tlie' elev'a-ti-ng conveyorand there its quired to operate the latter, especially during low temperature periods of operation.

I have found that the usefulness and practical value of the material heating means above described may be substantially enhanced by providing means for retarding escape to the atmosphere of the warm air rising from the hopper and the Warm gases issuing from the discharge spout of the conveyor. To this end I extend a pair of cables 99 from the upper front corners of the conveyor casing to the forward upper corners of the material bin, and a similar pair of cables 99' from the upper rear corners of the conveyor casing to the upper rear corners of the material bin; said cables and the top wall of the conveyor casing forming a support for a canopy 100 of heavy canvas or like material, which functions as a heat retaining hood or cover for the binand conveyor casing. This canopy, especially when made of rubber or rubberized cloth, also serves to exclude rain and snow and facilitates the operation of the machine in stormy and cold weather by preventing wetting and freezing of the stone and sand which would interfere with the free fiow of the latter, as well as holding in the heat.

I claim:

1. The combination with a storage hopper for paving material, an upright conveyor casing adjacent to said hopper, and an elevating conveyor in said casing, of means for preventing freezing of material in said hopper and conveyor casing comprising a substantially horizontal pipe extending through said hopper and discharging into said casing, and means for supplying a heating medium to said pipe.

2. The combination with a storage hopper for paving material, an upright conveyor casing adjacent to said hopper, and an elevating conveyor in said casing, of means for preventing freezing of material in said hop:

per and conveyor casing, comprising a substantially horizontal heating coil extending through the lower portion of said hopper, one end of said coil discharging into said casing at a point opposite the ascending limb of said conveyor, and means for supplying a burning gas to the other end of said coil.

3. The combination with a storage hopper for paving material formed with downwardly and inwardly convergent bottom walls, an upright conveyor casing adjacent to said hopper, and an elevating conveyor in said casing, of a substantially horizontal heating coil in said hopper, said coil extending through and supported by opposed bottom walls with one end thereof discharging into said casing, and means for supplying-a heating medium to the other end of said coil.

4. The combination with a storage hopper for paving material formed with downwardly and inwardly convergent bottom walls, an

upright conveyor casing adjacent to said hop- ROBERT W. FIEROH. 

